FEYN CALC SYMBOL

DiracReduce


reduces all four-dimensional Dirac matrices in exp to the standard basis (S,P,V,A,T) using the Chisholm identity (see Chisholm). In the result the basic Dirac structures are wrapped with a head DiracBasis. I.e., S corresponds to DiracBasis[1], P : DiracBasis[DiracMatrix[5]], V: DiracBasis[DiracMatrix[mu]], A: DiracBasis[DiracMatrix[mu, 5]], T: DiracBasis[DiracSigma[DiracMatrix[mu, nu]]]. By default DiracBasis is substituted to Identity. Notice that the result of DiracReduce is given in the FeynCalcExternal-way, i.e.,evtl. you may have to use FeynCalcInternal on the result.